Cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study

Abstract

ObjectivesThe primary aim was to examine exposureresponse relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sexspecific exposure-response relationships. The secondary aim was to examine the time window of relevant exposures. Methods We conducted a nationwide register study of all persons born in Denmark (1933Denmark ( -1977, who had at least 5 years of full-time employment. In the follow-up period (2003)(2004)(2005)(2006)(2007)(2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis. Results The adjusted OR (OR adj ) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure-response relationships were similar for men and women, when assessed using a relative risk scale. The OR adj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%. Conclusions Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure-response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures.

Neck and shoulder muscle activity among ophthalmologists during routine clinical examinations

“…(Schall Jr et al 2014 While estimates of muscular effort observed in this study were relatively low, the repetitive nature of ophthalmologic examinations and their cumulative effects over time may still contribute to the high prevalence of musculoskeletal pain among ophthalmologists. Several prospective studies have suggested that cumulative exposure to sustained, forceful muscular exertions may contribute to neck and shoulder pain among workers in various occupations (Dalbøge et al 2014;Hanvold et al 2013). Furthermore, duration of computer and mouse use, the clinical task observed to be most frequently performed among ophthalmologists in the current study, has been causally linked to musculoskeletal symptoms of the neck and arm (Blatter and Bongers, 2002;Jensen et al 2002;Marcus et al 2002;Waersted et al 2010).…”

Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows

“…We used data from a nationwide cohort study, which included the entire Danish working population as described previously 6. The cohort included all persons born in Denmark (excluding Greenland) between 1 January 1933 and 31 December 1977, who were alive and lived in Denmark on 31 December 2002 according to the Civil Registration System,12 and had at least 5 years of full-time employment between 1 January 1993 and 31 December 2007 according to the Supplementary Pension Fund Register 13.…”

“…Persons were excluded in case of surgery for any shoulder disorder before 31 December 2002 according to the Danish National Patient Register 12. The cohort comprised 2 374 403 persons with 14 118 first-time events of surgery for SIS during follow-up from 1 January 2003 to 31 December 2008 6. Follow-up time was calculated from 1 January 2003 or the year after they reached 5 years of full-time employment, whichever came later, until surgery for SIS or censoring due to surgery for any other shoulder disorder, death, disappearance, emigration (including change of address to Greenland) or 31 December 2008, whichever came first 6.…”

“…Within this time window, we found indications of cumulative effects because the risk increased gradually when we extended the number of years contributing to the cumulative exposure estimates from 2 to 10 years back in time 6. To obtain cumulative exposure measures, we used the well-known pack-year concept of smoking based on standardised measures of exposure intensity multiplied by durations of exposure (years), rather than using seniority, which does not account for exposure intensities.…”

Reduction of Biomechanical and Welding Fume Exposures in Stud Welding

“…With the exception of the upper trapezius, mean muscle activation levels were also reduced during use of the upright system. Although cumulative exposure to sustained and/or forceful muscular exertions is associated with musculoskeletal health outcomes (Hanvold et al, 2013;Dalboge et al, 2014), the magnitude of risk reduction associated with a given reduction in muscle activation is not well characterized. Therefore, while the observed reductions in biomechanical loading are mostly positive, definitive conclusions about the potential of the upright system to prevent musculoskeletal health outcomes are premature.…”